# An Unusual Presentation of Propylthiouracil-Induced Immunoglobulin A Vasculitis With Positive Anti-proteinase-3 and Anti-myeloperoxidase Antibodies

## TL;DR

A 57-year-old woman developed IgA vasculitis after taking PTU, showing that PTU can cause this rare condition.

## Contribution

This case report highlights a rare instance of PTU-induced IgA vasculitis with specific antibody findings.

## Key findings

- The patient showed pancytopenia and ecchymoses linked to PTU use.
- Biopsy confirmed IgA vasculitis with elevated anti-proteinase 3 antibodies.
- Symptoms improved after stopping PTU, supporting a causal relationship.

## Abstract

Propylthiouracil (PTU) has been identified as a known cause of anti-neutrophil cytoplasmic antibodies-associated vasculitis. However, the association between PTU and immunoglobulin A (IgA) vasculitis remains uncertain due to its rarity and diverse clinical presentation. Here, we report the case of a 57-year-old female with a past medical history of chronic leukopenia and Graves’ disease treated with PTU that presented with pancytopenia and widespread non-blanching ecchymoses on the bilateral legs. A punch biopsy of the medial leg demonstrated IgA vasculitis and autoimmune antibody analysis revealed increased levels of anti-proteinase 3 antibodies compared to anti-myeloperoxidase antibodies. These findings led to the diagnosis of PTU-induced IgA vasculitis. Following the discontinuation of PTU, there was marked improvement in the appearance of the patient’s cutaneous manifestations and hematological indices.